Just replaced the HD inside my Sky HD receiver with a 750Gb Seagate in an external Icy Box case. It's not too difficult to do and gives some extra flexibility. Copied over all the unwatched progs using the copy app that's downloadable. Sorry can'r remember what it's called but a Google and Digital Spy search will reveal all.
The interesting thing is I'm sure it now sounds better. The bottom end is less thich and as an example bass players on Later are easier to follow. Mechanical noise from the new HD is a bit louder. I'm still deciding whether to keep the fan on the Icy Box on medium and have a HD around 35C or turn it off and accept 45-50C. Both are fine spec wise but I just feel happier with a cooler drive but it comes with a price of fan noise.

Any one else with a similar experience?

My limited opinion...

Being happy with HDD temperature is not an issue for me. My breif interpretation of Google's tests on their hard disc arrays, suggests that failure is more to do with the temperature difference (delta), than the maximum temperature a HDD can run at.

see here:- http://labs.google.com/papers/disk_failures.pdf

Its like treating a car engine well. Let it warm gradually and leave it running over a longish distance, rather than running it for a 5 min trip every day.

As to the perceived sound quality improvement, this can be down to a multitude of things:- components used in the batch, software, power consumption, to name a few items (I am sure there are a couple of people here who could add more technical detail...).

I'd have to do a direct A/B test to be 100% convinced though.

I also think that certain drives, usually ones fitted to PVR's etc, are manufactured (or tweaked in software) for quieter access noise too.

(although I don't have any proof on this as yet...).

There is a feature called AAM = Automatic Acoustic Management.
You will find an explanation and links to software to enable this feature here:

http://en.wikipedia.org/wiki/Automatic_Acoustic_Management

http://www.heise.de/ct/ftp/suche/ergebnis?rm=result;q=a...ctsi.shtml;words=AAM

search for "aam" to find the software. use it at your own risk of course.

That's interesting about the Seagate drives. I assume they use some in-house solution then?

I know the DB35.3 series well and they are pretty dam quite.

I'd be very interested if anybody knows of any utils to help quieten Seagate drives as they can be a tad noisy